Sony is going to launch dual-SIM options of both Xperia X and Xperia X Performance. The white papers of the devices have been recently uploaded on Sony's Dev Portal, and we found some interesting info inside.

Apparently both Xperia X and Xperia X Performance will feature 64GB internal storage, double the amount of their single-SIM flavors. The firmware will occupy about 15.4GB of those, and 48.6GB will be available for your apps, multimedia, and files.